teems/Enclave/obliv.hpp

#ifndef __OBLIV_HPP__
#define __OBLIV_HPP__

#include <vector>

// Routines for processing private data obliviously

// Obliviously tally the number of messages in the given buffer destined
// for each storage node.  Each message is of size msg_size bytes.
// There are num_msgs messages in the buffer.  There are
// num_storage_nodes storage nodes in total.  The destination storage
// node of each message is determined by looking at the top
// DEST_STORAGE_NODE_BITS bits of the (little-endian) 32-bit word at the
// beginning of the message; this will be a number between 0 and
// num_storage_nodes-1, which is not necessarily the node number of the
// storage node, which may be larger if, for example, there are a bunch
// of routing or ingestion nodes that are not also storage nodes.  The
// return value is a vector of length num_storage_nodes containing the
// tally.
std::vector<uint32_t> obliv_tally_stg(const uint8_t *buf,
    uint32_t msg_size, uint32_t num_msgs, uint32_t num_storage_nodes);

// Obliviously create padding messages destined for the various storage
// nodes, using the (private) counts in the tally vector.  The tally
// vector may be modified by this function.  tot_padding must be the sum
// of the elements in tally, which need _not_ be private.
void obliv_pad_stg(uint8_t *buf, uint32_t msg_size,
    std::vector<uint32_t> &tally, uint32_t tot_padding);

// For each excess message, convert into padding for nodes that will need some.
// Oblivious to contents of message buffer and tally vector. May modify message
// buffer and tally vector.
void obliv_excess_to_padding(uint8_t *buf, uint32_t msg_size, uint32_t num_msgs,
    std::vector<uint32_t> &tally, uint32_t msgs_per_stg);
#endif